Refrigerator



Dec. 11, 1945. F. NEWMAN REFRIGERATOR Filed July 21, 1943 InventorDeibert F. Nevvvvxaurw Hus Attorneg.

Patented Dec. 11, 1945 REFRIGERATOR Delbert F. Newman, Schenectady, N.Y., assignor to General Electric Company, a corporation of New YorkApplication July 21, 1943, Serial No. 495,639

6 Claims.

My present invention relates to refrigerators including cabinets havinga plurality of temperature zones and more particularly to arrangementsfor minimizing undesired condensation of moisture within the highertemperature zones.

This is a continuation-impart of my copending application, Serial No.422,894, filed December 13, 1941, and assigned to the same assignee asthe present application.

Refrigerators have heretofore been proposed and constructed whichcomprise cabinets in which the available storage space is divided intodifierent temperature zones. For example, a freezing compartment and afood storage compartment may be arranged adjacent each other in thecabinet and quite frequently the freezing compartment is arrangeddirectly above the higher temperature food compartment. The foodcompartment is usually designed to be operated at a relatively hightemperature such as 45 F., for example, for the general storage of foodsat relatlvely high humidity. The separation of the freezing zone and thefood storage zone may be accomplished by providing an insulatingpartition completely or substantially eliminating direct communicationbetween the two compartments and refrigerating apparatus is provided forsuitably cooling the compartments to their required temperatures. Thewarmer food storage compartment is operated above the freezing point ofwater and at a relatively high humidity. Under certain conditions ofoperation the inherent cooling of the partition due to the operation ofthe freezing compartment cooler will be sufficient to cause acondensation of moisture on the wall of the food compartment adjacentthe freezing compartment. This condensation is objectionable since itbecomes necessary to provide some arrangement for conducting away andremoving the condensate. Condensation is particularly objectionable whenit occurs on the top wall of the food storage compartment from which itmay drip onto the articles stored in the compartment. Accordingly, it isan object of my invention to provide a refrigerator having compartmentsmaintained at different temperatures and comprising an improvedarrangement for minimizing the transfer of heat from the air in thehigher temperature compartment directly through the partltion betweenthe compartments to the cooling element in the lower temperaturecompartment.

Further objects and advantages of my invention will become apparent asthe following de scription proceeds, and the features of novelty whichcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming part of this specification.

For a better understandin of my invention, reference may be had to theaccompanying drawing in which Fig. 1 is a perspective view of a portionof a refrigerator cabinet of the domestic type embodying my invention,Fig. 2 is an enlarged sectional view of a portion of the cabinet of Fig.1 on the line 2-2 thereof, and Fig. 3 is a graph of the temperaturegradients prevailing in portions of the refrigerator of Fig. 1.

Briefly, the refrigerator illustrated in the drawing comprises athermally insulated cabinet divided into two compartments by a thermallyinsulated partition. The upper compartment is cooled by a freezing unitand the lower compartment by a refrigerating system of the secondarytype having its condensing portion arranged in heat exchangerelationship with the freezing unit. The arrangement of the compartmentsis such that there is a tendency for the partition to be substantiallycooled by the operation of the freezing unit so that the temperature ofthe wall of the partition adjacent the lower compartment may be so lowthat condensation of moisture results. In order to prevent thecondensation of moisture, the side of the partition adjacent the lowercompartment is supplied with heat generated in the refrigerating machineduring the operation thereof so that the temperature of that side ismaintained in the neighborhood of the temperature of the air in thelower compartment. This minimizes the transmission of heat from thelower compartment through the partition.

Referring now to the drawing, the refrigerator shown in Fig. 1 comprisesa cabinet l0 having thermally insulated walls divided by a partitioninto an upper compartment 8 and a lower compartment 9 by a thermallyinsulated partition ii. The upper compartment l is a freezing or coldcompartment closed by a door I! and provided with a primary refrigerantevaporator or cooling unit I3. The lower compartment is provided with athermally insulated door I4 and is cooled by a secondary typerefrigerating system comprising a closed refrigerant circulating conduitformed to provide a condensing portion ii in heat exchange relation withthe evaporator l3 and a refrigerant vaporizing portion ii in heatexchange relation with the lower food compartment. The secondary systemis a form of heat transfer device frequently employed, the closedconduit being partially filled with a vaporizable liquid; the liquid isvaporized by the absorption of heat in the evaporating portion l8 and iscondensed in the portion I5, the liquid returning to the portion It bygravity. The walls of the cabinet l comprise an outer sheet metal casingI Ila and a sheet metal inner liner II spaced therefrom, the space beingfilled with thermal insulation. The top and bottom walls 01' thepartition ll indicated, respectively. at I8 and I9 are also constructedof sheet metal, and the spaces between the edges of the metal sheets ll,I8 and I9 and the outer casing Illa are closed by breaker strips H ofsuitable nonhygroscopic material of low thermal conductivity. Theevaporating portion It or the secondary system is secured in direct heatexchange relation with the liner II along one side wall of the lowercompartment. Liquid refrigerant is supplied to the evaporator l3 from anair cooled condensing and liquefying unit mounted on the back of thecabinet I0. the liquid being conducted to the evaporator through aliquid line or capillary tube 22. A refrigerant compressing andcirculating unit (not shown) is connected in the usual manher towithdraw refrigerant from the evaporator 13 through a suction line 23and to supply hot compressed refrigerant to the condehser 29.

During the normal operation 01 the refrigerating machine the doors I2and Il are closed and the evaporator I3 cools the upper compartment to asuitable freezing temperature while the lower compartment is cooled bythe secondary system IS, IS to a temperature above freezing butsutiiciently low to provide adequate preservation of food-stuffs. Thisarrangement makes it possible to maintain relatively high humidity inthe lower compartment 8 and renders it unnecessary to provide separateclosed containers for maintaining the high humidity required for certainfoods. Any suitable control systems arranged to operate in accordancewith good refrigeration practice to maintain the desired temperatures inthe upper and lower compartments may be employed. The control devicesthemselves form no part of the present invention and have, therefore.not been illustrated; a temperature adjusting knob 24 is shown on theupper panel of the evaporator I3.

During the operation of the refrigerator heat tends to flow from thehigher temperature compartment 9 through the partition II to the lowertemperature compartment 8 and thereby tends to reduce the temperature ofthe sheet metal wall I9 of the partition to a value lower than thetemperature of the air in the compartment ll; as a result moisture maycondense from the air in the compartment and collect on the wall I9 fromwhich it may drip onto articles placed on shelves in the compartment.

In order to prevent the condensation of moisture on the partition II, anarran ement is provided for supplying heat to the plate I9 to raise itstemperature to the temperature of the air in the compartment 9 or higherthereby preventing the transfer of heat from the air in the compartmentthrough the partition II. As shown in Fig. l a capillary tube 22 isprovided with a sinuous or zigzag portion 28 extending across the lowerside of the wall I9 in good heat exchange relation therewith. Compressedrefrigerant leaving the compressing unit is hot and is cooledsufiiciently to be condensed in the condenser 20, however, the liquidrefrigerant passing through the capillary tube 22 still contains asubstantial quantity of heat and the portion 28 of a capillary tubeutilizes this heat for raising the temperature of the plate IQ of thepartition H. The partition H is provided with suiilcient thermalinsulation to retard the cooling of the plate II adjacent the liner I'I.

' T2 to the wall I9 at the temperature T4.

during the off period of the refrigeration cycle when additional liquidrefrigerant is not being supplied to the tube 22. It will readily beunderstood by those skilled in the art that the amount of insulation inthe partition II may be determined with a view to preventing an unduefall in temperature of the plate I9 during the off period. Portions ofthe capillary tube 22 may be arranged in heat exchange relation with thesuction line 23 in a manner well known in the art to increase theefilciency of the refrigerating machine. For example, a portion 29 ofthe capillary tube between the condenser 20 and the portion 28 may beconnected in heat exchange relation with the suction line 23, and aportion 30 between the portion 28 and the evaporator I3 may also beconnected in heat exchange relation with the suction line. It will beunderstood that the heat exchange portions 29 and 30 are used only whenthere is more heating capacity in the liquid refrigerant in the tube 22than is required for heating the wall I9 of the partition.

The graph in Fig. 3 illustrates the temperature gradients prevailingbetween the air outside the refrigerator cabinet and the air in thecompartment 9 and the air in the compartment 8. In this figure the wallI0 may be considered as the left side wall of the compartment 9 asviewed in Fig. 1, the partition H being shown parallel to the side wailmerely in order to indicate the temperature gradient as a continuousdownwardly extending line. In Fig. 3 the horizontal line T1 representsthe ambient temperature outside the cabinet, the horizontal line T2 thetemperature within the compartment 9, and the horizontal line T3 thetemperature in the compartment 8. In passing from the ambienttemperature T1 to the wall Illa there is a drop in temperature indicatedat 3| through a stagnant layer or skin of air immediately adjacent thesurface 01 the wall. The temperature drop through the insulation isindicated at 32 and a drop 33 between the wall I! and the temperature ofthe air in the compartment 9 occurs in the stagnant layer of air Thewidth of the skin or stagnant layer of air has been exaggerated forpurposes of illustration, it being known in the art that there is ameasurable temperature drop between a wall and the air circulating overthe wall. The drops in gradients at temperature T: to temperature T:shown at 34, 35 and 36, correspond to the drops 3|, 32 and 33 in thewall of the cabinet Ill. It is evident that the temperature at thesurface of the wall I9 is lower than the temperature I: of the air inthe compartment 9. This air is therefore cool and condensation mayresult when the relative humidity is suflicient high. By providing theliquid line 28 in heat exchange with the sheet metal wall I9, thetemperature of the wall, for example, may be raised to a value at T4which is the same as the temperature of the wall I1 and it is thusobvious that no heat may be transferred from the air of the compartment9 at the temperature The wall I9 may, of course, be heated to anysuitable temperature at least as high as the temperature T: andpreferably at least as high as T4. It is clear that if the wall I9 isheated to the temperature T2 or higher there can be no transfer of heatfrom the air to the wall and, consequently, heat cannot be removed fromthe air to produce condensation of moisture on the well. By raising thetemperature of the wall to a value higher than T2 there is provided amargin of safety such that a drop of the temperature To during the "of!"period of the refrigerating cycle will not lower the temperature of thewall below the temperature T2, the lag in temperature reduction beingdue to the presence of the insu iation in the wall H. The temperaturegradient from the heated wall is to thewali I8 is indicated by thedotted line 31. When a cool surface such as provided by the evaporatorportion it of the secondary system exists in the compartment I, thetemperature of this surface Substantially determines the dew point ofthe air in the com partment 9 and moisture will not normally collect onthose surfaces which are at a higher temperature; however, when the door14 is opened there is a rush of warm moist air into the compartment 9.Thus upon opening the door some condensation may occur on the partitionH as well as on the cold side wall; however, the amount of moisturecollected in this manner is not sufficient to cause dripping of thecondensate. and after the door is closed any moisture condensed on theplate H evaporates and migrates to the colder surface.

While the secondary cooling system has been illustrated as arranged inheat exchange with one side wall of the compartment 9, it will beunderstood that this portion may be disposed wherever supplementalcooling is desired. For example, the cooling portion l6 may extendaround all the side walls and the bottom wall of the compartment. Thecondensing portion 15 of the secondary system may be disposed in anysuitable relationship with the evaporator [3 which provides suflicientcooling to maintain the secondary system in operation.

The particular arrangement of the capillary tube 28 on the sheet metalwall I9 is immaterial so long as an adequate distribution of the heat isobtained. For example, the tube may be secured to the plate by solderingor it may be formed as a suitable passage in the wall I9 as byconstructing the wall IQ of complementary sheet metal portions having azigzag path formed therethrough.

While I have described my invention in connection with a two-temperaturehousehold refrigerator in which the freezing compartment is arrangedabove the high humidity food storage compartment other applications willreadily be apparent to those skilled in the art. I do not. therefore,desire my claims to be limited to the particular construction shown anddescribed and I intend by the appended claims to cover all modificationswithin the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. A refrigerator comprising a cabinet having thermally insulated walls,a thermall insulated partition for dividing the interior of said cabinetto provide two compartments within said cabinet. refrigerating meansarranged in said cabinet for cooling said compartments, said means beingarranged to maintain one of said compartments at a lower temperaturethan the other of said compartments, said means tending to cool thesurface of said partition within said other compartment to a temperaturebelow the normal temperature of the air in said other compartment, andmeans disposed in heat exchange relation with said partltion on its sideadjacent said other compartment for maintaining the temperature of thesurface of said partition within said other compartment at least as highas the temperature of the air within said other compartment whereby thetransfer of heat from the air in said other compartment through saidpartition is minimized.

2. A refrigerator comprising a cabinet having thermally insulated wallsand a thermally insulated partition dividing said cabinet into afreezing compartment in the upper portion thereof and a food storagecompartment below the freezing compartment, means including a coolingelement arranged in said freezing compartment f or cooling bothcompartments of said cabinet and for maintaining said freezingcompartment at a lower temperature than said food storage compartment,said means tending to cool the surface of said Mrtition within said foodcompartment to a temperature below the normal temperatur of the air insaid food compartment, means for supplying liquid refrigerant to saidcooling element, and means disposed in heat exchange relation with theside of said partition adjacent said food compartment and utilizing heatof the liquid refrigerant for maintaining the temperature of the surfaceof said partition within said food compartment sufficiently high tominimize the transfer of heat from said food compartment through saidpartition to said freezing compartment.

3. A refrigerator comprising a cabinet having thermally insulated wallsand a thermally insulated partition dividing said cabinet into twocompartments. means including a cooling element arranged in one of saidcompartments for cooling both said compartments and for maintaining saidone compartment at a lower temperature than the other of saidcompartments, said means tending to cool the surface of said partitionwithin said other compartment to a temperature below the normaltemperature of the air in said other compartment, and means including aliquid line for supplyin liquid refrigerant to said cooling element, atleast a portion of said liquid line being disposed in heat exchangerelation with the side of said partition adjacent said other compartmentfor supplying heat to said side to maintain the temperature of thesurface of said partition within said other compartment sufficientlyhigh throughout the normal range of operation of said refrigerator tominimize the transfer of heat from said other compartment through saidpartition to said one compartment.

4. A refrigerator comprising a cabinet having thermally insulated wallsand a thermally insulated partition for providing two compartmentswithin said cabinet, said partition comprising sheet metal walls spacedapart and provided with thermal insulation therebetween, means includinga cooling element arranged in one of said com partments for cooling bothsaid compartments and for maintaining said one compartment at a lowertemperature than the other of said compartments, said means tending tocool the surface of said partition within said other compartment to atemperature below the normal temperature of the air in said othercompartment, means including a capillary tube for supplying liquidrefrigerant to said cooling element, at least a portion of saidcapillary tube being arranged in heat exchange relation with the one ofsaid metal walls of said partition adjacent said other compartment formaintainin the temperature of the surface of said one wall within saidother compartment sufficiently high throughout the normal range ofoperation of said refrigerator to minimize the transfer of heat from theair in said other compartment through said partition to said coolingelement.

5. A refrigerator comprising a. cabinet having thermally insulated wallsand a thermally insulated partition for providing two compartmentswithin said zabinet, said partition comprising sheet meta. walls spacedapart and provided with thermal insulation therebetween, means includinga cooling element arranged in on of said compartments for cooling bot);said compartments and for maintaining said one compartment at a lowertemperature than that of the other or said compartments, said meanstending to cool the surface of said partition within said othercompartment to a temperature below the normal temperature of the air insaid other compartment, means including a capillary tube for supplyingliquid refrigerant to said cooling element, a suc- :tlon line forremovin vaporized refrigerant from said cooling element, at least aportion of said capillary tube being arranged in heat exchange relationwith the one of said metal walls of said partition adjacent said othercompartment for maintaining the temperature of the surface of said onewall within said other compartment sufficiently high throughout thenormal range of operation of said refrigerator to minimize the transferof heat from the air in said other compartment through said partition tosaid cooling element, a portion of said suction line being arranged inheat exchange relationship with said capillary tube for limiting theamount of heat in the liquid refrigerant flowing to said portion of saidtube in heat exchange With said wall of said partition.

6. A refrigerator comprising a cabinet having thermally insulated wallsand a thermally insulated partition dividing said cabinet into twocompantments, a primary evaporator arranged in one 01' said compartmentsfor providing a freezing zone, a secondary cooling system having acondensing portion in heat exchange relation with said primaryevaporator and an evaporating portion arranged for cooling the other ofsaid compartments, said primary evaporator also tending to cool saidother compartment by the transfer of heat through said partition fromthe air in said other compartment, means for supplying liquidrefrigerant to said primary evaporator, and means arranged in heatexchange relation with the side of said partition adjacent said othercompartment and utilizing the heat of the liquid refrigerant supplied tosaid primary evaporator for maintaining the temperature of th surface ofsaid side within said other compartment sufficiently high throughout thenormal range of operation of said refrigerator to minimize the transferof heat from said other compartment through said partition to saidprimar evaporator whereby the lowest temperature in said othercompartment is determined by said evaporating portion of said secondarysystem.

DELBERT F. NEWMAN.

Certificate oi Correction Patent N 0. 2,390,808.

December 11, 1945.

DELBERT F. NEWMAN It is hereby certified that errors appear in theprinted specification of the above numbered patent requiring correction"sufiicient read sufliciently; page 3, first column, gage 4, firstcolumn, line 30, claim 5, after "said as follows: Page 2, second column,line 58, for

line 23, for plate 11" read late 19;

insert one; and that the sai Letters atent should be read with thesecorrections therein that the same may conform to the record of the casein the Patent Ofiice.

Signed and scaled this 21st day of May, A. D. 1946.

i m-i LESLIE FRAZER,

First Assistant Commissioner of Patents.

lated partition for providing two compartments within said zabinet, saidpartition comprising sheet meta. walls spaced apart and provided withthermal insulation therebetween, means including a cooling elementarranged in on of said compartments for cooling bot); said compartmentsand for maintaining said one compartment at a lower temperature thanthat of the other or said compartments, said means tending to cool thesurface of said partition within said other compartment to a temperaturebelow the normal temperature of the air in said other compartment, meansincluding a capillary tube for supplying liquid refrigerant to saidcooling element, a suc- :tlon line for removin vaporized refrigerantfrom said cooling element, at least a portion of said capillary tubebeing arranged in heat exchange relation with the one of said metalwalls of said partition adjacent said other compartment for maintainingthe temperature of the surface of said one wall within said othercompartment sufficiently high throughout the normal range of operationof said refrigerator to minimize the transfer of heat from the air insaid other compartment through said partition to said cooling element, aportion of said suction line being arranged in heat exchangerelationship with said capillary tube for limiting the amount of heat inthe liquid refrigerant flowing to said portion of said tube in heatexchange With said wall of said partition.

6. A refrigerator comprising a cabinet having thermally insulated wallsand a thermally insulated partition dividing said cabinet into twocompantments, a primary evaporator arranged in one 01' said compartmentsfor providing a freezing zone, a secondary cooling system having acondensing portion in heat exchange relation with said primaryevaporator and an evaporating portion arranged for cooling the other ofsaid compartments, said primary evaporator also tending to cool saidother compartment by the transfer of heat through said partition fromthe air in said other compartment, means for supplying liquidrefrigerant to said primary evaporator, and means arranged in heatexchange relation with the side of said partition adjacent said othercompartment and utilizing the heat of the liquid refrigerant supplied tosaid primary evaporator for maintaining the temperature of th surface ofsaid side within said other compartment sufficiently high throughout thenormal range of operation of said refrigerator to minimize the transferof heat from said other compartment through said partition to saidprimar evaporator whereby the lowest temperature in said othercompartment is determined by said evaporating portion of said secondarysystem.

DELBERT F. NEWMAN.

Certificate oi Correction Patent N 0. 2,390,808.

December 11, 1945.

DELBERT F. NEWMAN It is hereby certified that errors appear in theprinted specification of the above numbered patent requiring correction"sufiicient read sufliciently; page 3, first column, gage 4, firstcolumn, line 30, claim 5, after "said as follows: Page 2, second column,line 58, for

line 23, for plate 11" read late 19;

insert one; and that the sai Letters atent should be read with thesecorrections therein that the same may conform to the record of the casein the Patent Ofiice.

Signed and scaled this 21st day of May, A. D. 1946.

i m-i LESLIE FRAZER,

First Assistant Commissioner of Patents.

